With the development of technologies, rich types of media are introduced in the Session Initiation Protocol (SIP) and IP multimedia subsystem (IMS)-based multiparty communication systems. In a multimedia session, the network device or server may strictly restrict the media type. For example, in an ongoing session, only one voice stream and one video stream can be used. In this case, the network entity may judge the requested media type and media parameter in the session request.
In some scenarios, network device providers or operators may allow different media streams of the same media type to be used in a session. In this way, multiple voice streams or multiple video streams may be simultaneously sent to a user terminal in the session.
The possible causes are, on the one hand, network entities that perform certain functions in the session do not provide related media restriction functions, and thus multiple media streams of the same media type requested by the user can be used in the session; on the other hand, in some scenarios, for example, in a multilingual simultaneous interpretation system, multiple simultaneous interpretations use different voice streams in the session.
During the implementation of the present invention, the inventor discovers at least the following problems in the prior art.
In a multiparty communication system, especially in a push-to-talk over cellular client (PoC) service, it is not specified that the created session should use a fixed media type in a multimedia session and that only one media stream of a media type can be sent. In the prior art, multiple media streams of the same media type may be simultaneously sent to the user terminal. Generally, the user cannot normally use the multimedia session in multiple voice streams or multiple video streams. Thus, a processing manner is required for a server to filter the media streams or for a terminal to process the media streams. Because different types of media and media parameters may be used in different sessions and each session may involve different scenarios, a mechanism for processing or filtering media streams by the terminal or the server is required.